2-halogen-3-chloro-4-amino-1-methylbenzene-5-sulphonic acids and process of preparing them



7 atom.

Patented July 1931 i g I 1 1,815,747" UNIT D ST TES PATIENT t ee,

HERMANN WAGNER, 0F BAn-soDEN-A -TAUNUs, ALBERT KISSLING, or FRANKFORT- oN-THE-MAIN-HOCHST, ERNST HOTZ, on HATTERSHEIM, NEAR; FRANKFORT-ON- THE-MAINQAND WILHELM FITZKY, or FRANKFORT-ON-THE-MAIN-HOCHST, emu MANY, Ass eivoas ro. GENERAL ANILInE'WoRKs'INo on NEW YORK, N. Y.; .A

- CORPORATION OF DELAWARE z-rrAnoenn-s-oH oRo-aAi/rrivo-i-ivrnrnynnnnznnns-sunrnomc ACIDS AND: rRocEss a a L on PREPARING THEM, z I

No Drawing. Application filed August s 1929, Serial No. 384,492, and in Germany September 'I, 1 928.

7 The present invention relates to 2-halogen- 3 chloro 4: amino-l-methylbenzene 5 -sul'- phonic acids and a process of preparing them,

more particularly itrelates to compounds of '5' the following general formula:

HOaS;

0 wherein X staiidsfor a chlorine or a bromine We have found that these compounds which have been unknown up" to the time of the present invention are obtainable uniformly and in a manner which can easily be carried out in practice by treating a compound of the following general formula:

, I CH3 wherein X stands fora chlorine or a bromine atom, either with concentrated sulfuric acid at about 170 G; to 200'C., orby causing one molecular proportion'of such a compound dissolved in concentrated sulfuric acid to re- 7 c act with onemolecular proportion of sulfuric anhydride dissolved in concentrated sulfuric acid. In this latter case the formationof the sulphonic acid sets in even at a considerably lower temperature, namely at amout 100 C. t0130 C. a f The following examples serve to illustrate our invention but they are not intended to limit it thereto, the parts being by weight. 1) 176 parts of 2.3-dichl0ro-4-amino-1- methylbenzene, obtainableiaccording to U. S. patent specification No; 1,712,173, are heated for about 1 to 3 hours with about 250 to 450 parts of concentrated sulfuric'acid up to a temperature of 170 C. to 200 0., while stirring. After cooling the mixture is poured on about 1,000 parts of pounded ice. The2.3-difiltered alone at elevated temperature, as, for instance,

chloro 1amino-1-inethylbenzene-5-sulphonic this operation and is y suction. The compound may be purified by redissolution by way of its magnesium salt. The sulphonic acid thus obtained is a white powder; it forms'a sparingly soluble sodium salt and more readily sol,- ublecammonium or magnesium salts; it can veryeasily be diazotized.

(2) 220.5 1 parts of 2-bromo-3-chloro-4- amino-l-methylbenzene obtainable according is 'preci itated during toathe process of the above mentioned patent specification by starting from 2-bromo-4} amino-l-methylbenzene, are treated as de I zene-fi-sulphonic acid of the following formuscribed in Example 1.

scribed in the precedingexample with about (3) 176 parts of 2.3-dichloro-4amino-1- I methylbenzene are dissolved in about '500 parts of sulfuric acid monohydrate,150parts ofvfuming sulfuric acidcontaining about 60 to 65 per cent of sulfuric anhydride are then addedand the mixture is heated for about 2 hours up to 100 to 130 0., while stirring. After cooling the mass is poured upon ice and the 2.3 dichloro+t-amino-l-methylbenzene- 5-sulphonic acid precipitating during this operation is isolated and purified as stated in example'l. The compound thus obtained is identical with that obtained according to, Example 1 and has the above given formula.

2 Lamp/a7 We claim 2' c V 1. The process which Comprises heating a compound of the following general formula:

wherein X stands for a chlorine or a bromine atom, with Concentrated surf-uric acid to a temperature of about 17 0 C. to about 200 C. a

2. The process which comprises heating V 253 diohloro l-amino-l-inethylbenzene with concentrated sulfuricacid to a temperature of about 17 0 (Ito alomitQOO C.

'3. The process which comprises heating 1 7 part by weight of 2L3-diehlorol-amino-1- methylbenzene with a quantity of about 1 to about 2 parts by weight of concentrated sulfuricaoid to a temperature of about 17 0 C. to 200 C. for about 11/ to 3 hours, while stirring. I l Z Q rAs new products, theoompounds of the following general formula v V CH3 Ho s" i p I V p v wherein X stands for a chlorineor a' bromine atom, being white powders and forming sparingly soluble sodiumbut lnorereadily soluble ammonium or magnesium salts and being ery easily diazotizable.

5.. As a new product, the 2.3-dichloro-4- amino-Tl-niethyIbenZen'e 5 sulphonic acid of thforlfiulai A r CH3 being a white powder, forming a sparingly soluble sodium salt and more readily soluble ammonium or magnesium salts and be I ing Very easily diazotizable. I c lntestlmony whereof, we affix our signaturesf HERMANN WAGNER.

ALBERT KISSLING. ERNST HOTZ- WILHELM FITZKY; 

